On my Patreon feed, Lindy asked: I am trying to choose from among the green emulsifiers, and I was wondering if you are aware of any that are more or less comedogenic than others" Any time I create for my daughter and best friend, it is the number-one issue. I know there are no guarantees, but I was just wondering ...  I hate to experiment on their faces when any misstep can cause distress, especically if there are some that are known to be acne-challenging. 

What a great question! However my answer is...I have no idea. Please read on to see why I'm saying this!

What does it mean for something to be comedogenic" It means that an ingredient or product causes the formation of comedones (blackheads) in a relatively short period of time. Blackheads form when the outer layers of our skin do not shed properly and the hair follicle is blocked. The blackhead part comes from the oxidation of fatty acids on the surface in the skin. Scienticians still aren't really sure what causes this lack of desquamation. Formation of comedones are not accompanied by skin redness.
Most of the scores we see for comedogenic ingredients come out of the rabbit ear assay or rabbit ear model, which is a test in which "the test material or an extract is applied directly to intact and abraded sites on the skin of a rabbit. After a 24-hour exposure, the material is removed and the sites are scored for erythema and edema." (redness and swelling). As in the name, the test...